This is a randomized, multi center, double-masked, placebo-controlled study of recombinant human interleukin eleven (rhIL-11) in subjects with active Chron's Disease. The objectives of this study are: PRIMARY: 1. Assess the efficacy of rhIL-11 in subjects with active Chron's disease who are not receiving prednisone therapy 2. Evaluate the effect of varied rhIL-11 dosing schedules SECONDARY: 1. Assess the safety of rhIL-11 in subjects with active Crohn's disease 2. Assess the effect of varied rhIL-11 dosing schedules on subjects' quality of life 3. Explore the potential of rhIL-11 treatment as a cost-effective therapy for Crohn's disease